<h1>qrcode works!</h1>
<div class="qrcodeImage">
  <qrcode #qrcode
          [qrdata]="qrData"
          [allowEmptyString]="true"
          [ariaLabel]="'QR Code image with the following content...'"
          [cssClass]="'center'"
          [colorDark]="'#000000ff'"
          [colorLight]="'#ffffffff'"
          [elementType]="'canvas'"
          [errorCorrectionLevel]="'M'"
          [imageSrc]="'./assets/angular-logo.png'"
          [imageHeight]="60"
          [imageWidth]="60"
          [margin]="2"
          [scale]="1"
          [title]="'下载二维码'"
          [width]="300"
  ></qrcode>
</div>
<div class="downloadButton">
  <button (click)="saveQRCodeAsImage(qrcode)">Download QR Code Image</button>
</div>
